Complex Regional Pain Syndrome (CRPS) is a neuropathic pain disorder that is characterized by: 1) Severe pain beyond the area of injury; 2) Autonomic dysregulation; 3) Neuropathic edema; 4) A movement disorder, atrophy and dystrophy. It is most often caused by a fracture, soft-tissue injury or surgical procedure and is divided into Type I, in which no nerve lesion is identified (classic reflex sympathetic dystrophy), and Type II where a specific nerve has been damaged (causalgia). In addition to the peripheral manifestations, there are many internal medical complications whose etiology is often not appreciated. This article will examine how CRPS affects the systems of: cognition; constitutional, cardiac, and respiratory complications; systemic autonomic dysregulation; neurogenic edema; musculoskeletal, endocrine and dermatological manifestations; as well as urological and gastrointestinal function.